[SDK-163]: Added Handling Users section

Author: echarrod

README.md

@@ -113,16 +113,26 @@ def auth():
     activity_details = client.get_activity_details(request.args['token'])
 ```
 
-## Profile Retrieval
+## Handling Users
 
-When your application receives a token via the exposed endpoint (it will be assigned to a query string parameter named `token`), you can easily retrieve the user profile by adding the following to your endpoint handler:
+When you retrieve the user profile, you receive a user ID generated by Yoti exclusively for your application.
+This means that if the same individual logs into another app, Yoti will assign her/him a different ID.
+You can use this ID to verify whether (for your application) the retrieved profile identifies a new or an existing user.
+Here is an example of how this works:
 
 ```python
+client = Client(YOTI_CLIENT_SDK_ID, YOTI_KEY_FILE_PATH)
 activity_details = client.get_activity_details(request.args['token'])
-user_profile = activity_details.user_profile
-    return render_template('profile.html',
-                           **user_profile)
 
+user_id = activity_details.user_profile.get('user_id')
+selfie = activity_details.user_profile.get('selfie')
+given_names = activity_details.user_profile.get('given_names')
+family_name = activity_details.user_profile.get('family_name')
+phone_number = activity_details.user_profile.get('phone_number')
+date_of_birth = activity_details.user_profile.get('date_of_birth')
+postal_address = activity_details.user_profile.get('postal_address')
+gender = activity_details.user_profile.get('gender')
+nationality = activity_details.user_profile.get('nationality')
 ```
 
 ## Running the examples